Wellbore cleanup tools such as those offered by Baker Hughes Incorporated, a GE company under the name VACS have been in use to remove and capture borehole debris. These tools work on an eductor powered by tubing flow from the surface to draw debris laden flow into the bottom of the tool. The flow enters through an inlet tube surrounded by a debris reservoir. The heavier debris settles into the reservoir while smaller debris continues up the tool drawn by the eductor fluid inlet at which there is a reduced pressure due to the connected motive fluid. The drawn fluid is moved through a screen inside the tool to further remove particulates. The eductor discharge is laterally to the surrounding annulus where the flow can go in two opposed directions. Most of the flow goes to the surface through the annulus and the rest goes down the annulus and is drawn into the open lower end of the tool with fresh debris laden flow. Some examples of this tool are shown in U.S. Pat. No. 7,472,745 and more recently as improved in U.S. Pat. No. 9,494,005. Flapper valves to retain debris from falling out of a tool once brought into the tool and using sensors to detect well conditions in bottom hole assemblies in a jet cleaning application are shown in US 2009/0151936.
What the reverse circulation debris cleanup devices have not had in the past is a way to control the well as the devices are run in or being removed. The collected debris reservoirs have also increased in length to over 1000 meters below eductor 34. The problem this causes is that the tool will have wall openings that cannot be captured in a lubricator because of limited length of lubricators of about 30 meters. This make a need for isolating the formation for running in or removal of the debris cleanup tool. The situation is schematically illustrated in FIG. 1. The debris removal tool 10 has a debris inlet 12 at the lower end. The lower end 12 is open to flow during normal operation. Arrows 14 schematically illustrate a pressure surge from the formation below which needs to be controlled. Presently such a pressure surge can communicate to the surface despite the fact that rams 16 on a blowout preventer close off the annulus 18 with arrows 20 schematically representing the closure in the annulus 18. The flow represented by arrows 14 continues unhindered to the surface despite the annulus 18 being secured with rams 16.
The present invention addresses this shortcoming in the prior designs by providing a closure against pressure surges from the formation before they even begin. The device adds a valve that stays open for normal operation as shown in FIG. 2 and that can be triggered to close with a sensor that detects a predetermined condition to shut the isolation valve within the tool housing to control the well with the assistance of the closure of the rams to secure the surrounding annulus. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings with the understanding that the full scope of the invention is to be determined by the literal and equivalent scope of the appended claims.